Vehicle effects on in vitro heparin release and skin penetration from different gels

Abstract

The effects of different gel bases, such as Carbopol 934, Pluronic F-127 and Methocel J5MS, on both heparin release from gel formulations and its penetration through excised human skin were investigated. Heparin release rate from the gel examined increased in the order: Methocel < Pluronic < Carbopol and no inverse correlation existed between the heparin apparent diffusion coefficient and the gel viscosity values. Heparin steady state flux values through human skin were not affected by the different gel base used and were lower than the release rates from the gels. Furthermore, the ability of Azone and N-methylpyrrolidone to increase heparin skin penetration from gels was assessed. The addition of 5% Azone or 10% N-methylpyrrolidone to Carbopol gels increased heparin flux through the skin about 4-fold compared to control gels.